Software providers often introduce users to their applications by first providing users with limited-function versions of those applications, generally at low or no cost. After a user tries out a limited-function version, providers hope that the user will like it and purchase a full-function version. Examples of this conventional approach include a low-cost version of a PDF reader that can read but not edit PDFs, a free download of a 30-second clip of a music video rather than the full-length video, and a free gaming application that cannot reach higher game levels or be played for more than a set period of time.